Cannabis Abuse or Dependence During Pregnancy: A Population-Based Cohort Study on 12 Million Births

Cannabis is the most commonly used recreational drug during pregnancy in the United States. This study aimed to describe the rate of cannabis dependence or abuse use during pregnancy and its effect on obstetrical and neonatal outcomes.

A retrospective population-based cohort of births in the United States between 1999 and 2013 was created using data from the National Inpatient Sample. Births to mothers who reported cannabis dependence or abuse were identified using ICD-9 codes, and the effect on various obstetrical and neonatal outcomes was assessed using logistic regression, adjusting for relevant confounders (Canadian Task Force Classification II-2).

A total of 12 578 557 births were included in our analysis. The incidence of cannabis abuse or dependence rose from 3.22 in 1000 births in 1999 to 8.55 in 1000 births in 2013 (P < 0.0001). Women reporting cannabis dependence or abuse were more likely to have a preterm premature rupture of membranes (odds ratio [OR] 1.46; 95% confidence interval [CI] 1.35-1.58), a hospital stay of >7 days (OR 1.17; 95% CI 1.11-1.23), and an intrauterine fetal demise (OR 1.50; 95% CI 1.39-1.62). Neonates born to exposed mothers had a higher risk of prematurity (OR 1.40; 95% CI 1.36-1.43) and growth restriction (OR 1.35; 95% CI 1.30-1.41).

Cannabis use during pregnancy steadily increased over the study period. Users of cannabis during gestation were more likely to have adverse outcomes during delivery and require longer periods of hospitalization. Neonates born to exposed mothers were more likely to be born preterm and underweight.